Date: Sun, 28 Apr 2013 18:13:45 -0700 From: Tim Kientzle <tim@kientzle.com> To: Tim Kientzle <tim@kientzle.com> Cc: freebsd-arm@freebsd.org Subject: Re: BeagleBone Black Message-ID: <511086A4-37A1-40B5-867E-64996A49EBB8@kientzle.com> In-Reply-To: <BE864289-8FDA-4223-BB5E-33EFC31AA0A0@kientzle.com> References: <CANuCnH9XP3Jn30EWCuZ0AmQF6MA4q4U9GUB7LU=XXZEdp7ZJ8g@mail.gmail.com> <D74DF146-7E72-4A2A-B74B-A20758010166@kientzle.com> <26A08C89-95EA-463D-98C5-A471F8D15C90@freebsd.org> <BCB14F16-203D-4C9A-8318-4E7DF1F88E17@kientzle.com> <54A0884D-31D0-4FC6-BBB5-58E3D11050E6@freebsd.org> <F01F0BC9-8464-469C-B1FE-D0E6AC217164@freebsd.org> <77E91A57-7880-4908-8999-6115333F5002@kientzle.com> <517CEDBF.3090102@g7iii.net> <BE864289-8FDA-4223-BB5E-33EFC31AA0A0@kientzle.com>
next in thread | previous in thread | raw e-mail | index | archive | help
On Apr 28, 2013, at 10:03 AM, Tim Kientzle wrote: > On Apr 28, 2013, at 2:37 AM, Iain Young wrote: >> On 28/04/13 08:13, Tim Kientzle wrote: >>=20 >>> The 4-pin adapter I got from Adafruit for use with Raspberry Pi = seems >>> to work just fine, though the CircuitCo documentation has the = instructions >>> wrong. It should be: >>> Black =3D> Pin 1 >>> Green =3D> Pin 4 >>> White =3D> Pin 5 >>=20 >> Hurm, I wonder what the other 3 pins are used for. They seem to be >> undocumented in the SRM >=20 > I believe they're unconnected. They're only there for compatibility > with the common FTDI TTL-232R-3v3 USB-to-serial > adapter that has a 6-pin connector. Adafruit has added a photograph of using their 4-wire adapter with the BB Black: http://www.adafruit.com/products/954 >=20 >>> Harumph. Looks like it always boots initially from the eMMC and >>> U-Boot then looks at the boot switch to decide whether to continue >>> from eMMC or uSD. >>=20 >> This would appear to be the default behaviour, but can be over-ridden >> if I read the SRM correctly. For a one off force to uSD boot, hold = down >> the "boot" button". See Page 57 of the SRM >=20 > Tried that, but from watching the serial console, it's still > loading U-Boot from the eMMC. It's U-Boot that actually looks > at that pin (there are some messages on the serial console > about U-Boot inspecting a GPIO pin). I was wrong. The point that was confusing me: The "boot switch" is *only* read when you apply power. Resetting the board doesn't read the boot switch; you have to actually remove power and then connect power while holding the switch. U-Boot does fiddle GPIO pins, but only to set some LEDs to indicate boot progress. >>> This sucks: the U-Boot on the eMMC doesn't have ELF support >>> nor API support so can't load and boot ubldr. Again, I was wrong. It actually is possible to build a micro-SD image and just boot it. So far, I have managed to build an image that would boot on either old or new BeagleBone. The build isn't quite repeatable --- I need to clean up some patches and fix a few loose ends. I was hoping to finish that tonight ... Tim
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?511086A4-37A1-40B5-867E-64996A49EBB8>